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R Cespuglio

Publications and source records attributed to R Cespuglio.

At least 91 records · Page 5Linked to original sources
PubMed1981

In vivo measurements by differential pulse voltammetry of extra-cellular 5-hydroxyindoleacetic acid in the rat brain.

The use of differential pulse voltammetry, performed with electrochemically treated carbon fiber electrodes, enables us to detect in vitro or in vivo, in the striatum of anaesthetized rats, an oxidation peak (3) at a potential of + 300 mV. Electrolytic or 5-7-dihydroxytryptamine lesions of the medial forebrain bundle are followed by a decrease of 59 and 62% respectively of this peak. Biochemical measurements are significantly correlated with the measured peak (3) and decreases. Thus, peak (3) increases obtained after injection of L-tryptophan and/or Reserpine, as well as the decreases observed after injection of Clorgyline or 3-hydroxybenzylhydrazine, confirm that peak (3) is dependent upon 5-hydroxyindoleacetic acid concentration. The detection of a peak (3) in the cerebrospinal fluid and its increase after injection of Probenecid reinforce this conclusion.

5,7-Dihydroxytryptamine↗
PubMed1980

Absence of light-dark entrainment on the sleep-waking cycle in mice with intact visual perception.

The influence of the light-dark schedule (12 h-12 h) on the sleep-waking cycle has been studied in anophthalmic mice: the 'eyeless' ZRDCT/An strain. The complete anophthalmic mice or the heterozygotous mice of the same strain with unilateral or bilateral eyeballs present a circadian organization of the sleep-waking cycle which is not dependent on the light-dark cycle. These results are different from sleep rhythms of C57Br mice recorded under the same experimental conditions. They indicate that the structures responsible for the circadian rhythmicity of sleep exist in all the 'eyeless' ZRDCT/An mice, but are not functionally linked with the visual system even in the mice with unilateral and bilateral eyeballs.

Animals↗
PubMed1980

In vivo electrochemical detection of catechols in the neostriatum of anaesthetized rats: dopamine or DOPAC?

Electroanalytical techniques for the in vivo measurement of neurotransmitters in brain tissue have been applied especially to the catecholamines, which are easily oxidizable. Measurements are, however, complicated by the presence of ascorbic acid (AA) in brain tissue. Lane et al. have been able to circumvent this problem, at least in part, by the application of differential pulse voltametry (DPV) to a surface-modified platinum electrode, obtaining distinct oxidation current peaks in recordings from the rat neostriatum which are attributed to AA and to dopamine (DA), respectively, but which are also unstable. We have recently described a new type of electrode, consisting of a pyrolytic carbon fibre 8 micrometers thick and 0.5 mm long. We now report that the DPV method used in conjunction with an electrochemical treatment of this electrode yields stable and reproducible peaks in which catecholamines and AA are resolved from each other. Moreover, pharmacological investigations suggest that the catecholamine peak measured in vivo in the rat neostriatum should be attributed to 3, 4-dihydroxyphenylacetic acid (DOPAC), suggesting that our technique may be a useful means of following dopaminergic activity in vivo.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1980

[In vivo measurement, by differential pulse voltammetry, of 5-HIAA in the striatum of the rat].

Differential pulse voltammetry, performed with electrically treated carbon fiber electrodes, enables us to detect in vitro or in vivo in the striatum of anesthetized Rats, an oxidation peak 3 at a potential of +300 mV. Electrolytic, or 5,7-dihydroxytryptamine lesions of the medial forebrain bundle are followed by a decrease of respectively 59 and 62% of this peak. Biochemical measurements are significantly correlated to the measured peaks 3 and troughs. Thus, peak 3 increases obtained after injection of L-tryptophane and/or reserpine, as well as the troughs observed after injection of clorgyline and/or NSD 1015 confirm that the peak 3 is dependent upon 5-hydroxyindolacetic acid (5-HIAA) concentration.

Animals↗
PubMed1980

[In vivo voltametric measurement of ascorbic acid and DOPAC in the striatum of the rat and guinea-pig].

Differential pulse voltammetry was performed with electrochemically treated carbon fiber electrodes. By this technique, ascorbic acid and catechol compounds were resolved in vitro in two distinct peaks. Similar oxidation peaks were obtained in vivo from the striatum of Rats and Guinea-Pigs. From electrochemical and pharmacological observations it is suggested that they correspond to the oxidation of extracellular ascorbic acid and 3,4-dihydroxyphenyl acetic acid (DOPAC).

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

[Effect of cooling and electrical stimulation of nuclei of raphe system on states of alertness in cat].

In cats prepared in a 'semi-chronic' manner (spinal cord transected, brachial plexus sectioned bilaterally) all states of alertness are present; their quantitative evolution is characterized by an immediate postoperative period with continuous wakefulness and a secondary period of recovery of the states of sleep, which are then maintained. In such a preparation, localized moderate cooling (+10 degrees C) of the nucleus raphe dorsalis induces slow wave sleep and paradoxical sleep; the same type of cooling of the nucleus raphe magnus induces wakefulness; however, the electrical stimulation of these two nuclei always induces wakefulness. Cooling of the nuclei raphe centralis or pontis suppresses only the 'ponto-geniculo-occipital' (PGO) waves. Colling of the nuclei raphe obscurus and pallidus induces wakedfulness, but stage I of slow wave sleep may occur. Treatment with p-chlorophenylalanine (PCPA) before making the semi-chronic preparation produces the classical syndrome characterized by cortical activation and continuous discharge of PGO waves; in this case cooling of the nucleus raphe dorsalis no longer induces slow wave sleep but only paradoxical sleep; after injection of DL-5-HTP, slow wave sleep is obtained again through cooling; this effect diminishes progressively.

5-Hydroxytryptophan↗
PubMed1978

[In vivo continuous electrochemical determination of dopamine release in rat neostriatum].

Polarographic micro-electrodes (carbon fiber, o. d. 8 micron) implanted in the Rat caudate nucleus, allowed a practically continuous in vivo monitoring (one measurement every 5 sec.) of the extra-cellular concentration of dopamine released by striatal dopaminergic terminals. Administration of amphetamine produced a reproducible increase of the oxidation current. This effect was suppressed after the selective degeneration of the striatal dopaminergic terminals following the injection of 6-OHDA into the substantia nigra or after inhibition of the synthesis of the amine by alpha methyl-p-tyrosin. After 5 hrs. this drug produced a 70% decrease of the oxidation current.

Animals↗
PubMed1978

Rhythmical activity of the rat's tongue in sleep and wakefulness.

Nine chronically implanted rats were used to study rhythmical activity of suprahyoidal muscles controlling tongue motility. This muscle group exhibited a fixed, regular rhythm of 5--8 c/sec during PS, not during SWS, resembling that observed when the awake rat drank, ate or groomed. In PS the tongue rhythm occurred less frequently than did eye movements and phasic nasolabial muscle activity; when it did, it was associated with such eye movements 80% of the time and 20% of the time before or after an episode of eye movements. A respiratory-related suprahyoidal EMG was observed in one rat to precede the onset of the diaphragm's EMG. Mechanisms for entraining phasic activity of extraocular, nasolabial and suprahyoidal muscles in PS are discussed.

Animals↗
PubMed1977

[Phasic activity in rats].

At the central level, in the rat, phasic activity has been recorded during paradoxical sleep and in acute conditions after injection of reserpine or parachlorophenylalanine. At the external level, during paradoxical sleep, the extraocular muscles lateral rectus, superior rectus and superior oblique are activated in both plastic and tonic manners. The muscles of the whiskers are also activated; these muscular activations are more often than not synchronous with the eye movements (80%). The time distribution of these ocular movements is homogenous. Reserpine induces phasic muscular activations of the extraocular muscles.

Animals↗
PubMed1976

Anatomical organization of the phasic activity produced by reserpine at the level of the oculomotor system.

The organization of the pathways responsible for the transmission of phasic electrical activity at the level of the oculomotor system was studied in the encéphale isolé cat which was injected with reserpine or exhibited spontaneous phases of paradoxical sleep. At the level of the VIth nuclei there are both ipsilateral and contralateral connections deriving from each generator. The ipsilateral pathway transmits an "inhibiting" potential eliciting electromyographic inhibition of the ipsilateral rectus muscle, and the contralateral pathway, an "activating" potential eliciting activation of the corresponding lateral rectus muscle. A medial saggital section from frontal plane APO, extending caudally to the VIth nuclei at frontal plan P9 is necessary to suppress the bilateral synchronization of phasic activities recorded from the VIth nuclei and the activation of the lateral rectus muscles. The areas responsible for phasic activity recorded at the level of the central visual and oculomotor systems have been delimited through brain transections. The pathways responsible for the transmission of phasic activity at the level of the IIIrd and IVth nuclei are contiguous with the ponto-geniculate pathways. This was demonstrated by electrocoagulation.

Abducens Nerve↗
PubMed1976

Evidence for the presence of eye movement potentials during paradoxical sleep in cats.

1. Phasic activities related to eye movements in the dark in abducens nucleus (N.VI), lateral geniculate body (LGB), visual cortex, and lateral rectus muscle were analyzed in 18 cats with chronically implanted electrodes during waking and sleeping. 2. N.VI waves, both during waking and sleeping, were multiphasic, and two distinct wave forms were noticed on either side of the pons. The N.VI waves preceded each ocular movement by 10--20 msec. 3. Both during waking and paradoxical sleep (PS), N.VI waves always preceded those occurring in the LGB. During waking, eye movement potentials (EMPs) in LGB followed the onset of the N.VI wave with a long (greater than 60 msec) and variable latency, but followed the end of the same wave with a rather constant delay (about 20 msec). During PS, two distinct populations of latency were observed between onset of the pontine waves and that of LGB waves. The latency of one population was less than 35 msec, and of the other more than 66 msec. 4. Since the LGB waves following N.VI waves with a long latency were similar in a number of respects to EMPs during wakefulness (EMPw), they were judged to be EMPs (EMPps), and were distinguished from LGB PGO waves, which followed N.VI waves with a short latency. Cortical EMPps were observed as well, but occurred about 8--10 times less frequently than the PGO wave. 5. In the light of the present results, the mechanisms responsible for EMP and PGO wave activities are discussed.

Abducens Nerve↗